虚词在下列4种情况应该用强读式：
1. 表示并列或对比（重读）
- It’s either you or me who must go.
- It’s my fault, not yours.
- He travels to and from New York several times a month.
2. 表示强调（重读）
- It was me who did it.
- it was she who was to blame.
3. 在句尾（强读不重读）
- What are you looking at?
- Who are you waiting for?
- Where did he come from?
- That was the only solution I could think of.
- Where are you going to?
4. 在非重读音节和人称代词之间（强读不重读）
- I’ve been waiting for you.
- I’m looking at him.
弱读的5种主要形式：
1. 元音弱化
- /æ/弱化为/ə/：an，am，and，as，at，have，has，had，can，shall，that，than
- /ʌ/弱化为/ə/：but，us，does，must，some
- /ɒ/弱化为/ə/：was，from，of
- /u:/弱化为/ə/：do，to，you（/jə/只在美国语音中使用，英国标准语音中很少使用）
- /ʊ/弱化为/ə/：should，would，could
- /ɔ:/弱化为/ə/：your，for
- /ɜ:/弱化为/ə/：her，were
- /ɑ:/弱化为/ə/：are
- /ɪ/弱化为/ə/：will
- /e/弱化为/ə/：them
- /eə/弱化为/ə/：there
2. 长元音缩短但音质不变
- /i:/缩短成/i/：the，he，she，me，we，be
- /u:/缩短成/u/：you
3. 省略
- 省略位于词首的/h/：he，him，his，her，have，has，had
4. 省略元音，辅音成为音节的主体
- from /frm/，them /ðm/，shall /ʃl/，can /kn/，some /sm/，than /ðn/
5. 省略辅音和元音
- and /ən，nd，n/
